For Windows:

Visicom Media’s AceFTP 3 Freeware is the easiest-to-use free FTP client software available for transferring files over the Internet.

Ace FTP 3 Freeware

Provided By: Visicommedia

For Mac OSX:

Cyberduck is an open source FTP and SFTP (SSH Secure File Transfer) browser licenced under the GPL with an easy to use interface, integration with external editors and support for many Mac OS X system technologies such as Spotlight, Bonjour, the Keychain and AppleScript.

Cyber Duck

Provided By: Cyber Duck